Time to calcitonin normalization after surgery for node-negative and node-positive medullary thyroid cancer

Abstract

Background: It remains unclear when postoperative serum calcitonin levels should be measured in patients with medullary thyroid cancer (MTC) and, specifically, whether this decision should be based on the preoperative calcitonin level or nodal status. Methods:A cohort of patients with previously untreated MTC was studied. Kaplan-Meier analyses, stratified by preoperative calcitonin level, nodal status and number of nodal metastases, were performed to determine time to calcitonin normalization after initial surgery, with statistical analysis by means of the log rank test.Results: Some 213 patients with node-negative and 182 with node-positive MTC were included in the study. Postoperative calcitonin levels normalized in a mean of 3⋅5 versus 3⋅7 days respectively among patients with preoperative calcitonin levels of 10-100 pg/ml (P = 0⋅815); 4⋅8 versus 5⋅3 days in those with preoperative calcitonin levels of 100⋅1-500 pg/ml (P = 0⋅026); 5⋅3 versus 9⋅9 days in patients with preoperative calcitonin levels of 500⋅1-1000 pg/ml (P = 0⋅004); and 6⋅6 versus 57⋅7 days among those with preoperative calcitonin levels exceeding 1000 pg/ml (P < 0⋅001). Calcitonin levels normalized in a mean of 4⋅7 days when nodal metastasis was not present, 5⋅2 days in those with one to five nodal metastases, 7⋅0 days in patients with six to ten nodal metastases, and 57⋅1 days among patients with more than ten nodal metastases. Postoperative calcitonin normalization curves paralleled each other in patients with node-negative MTC, but diverged in those with node-positive disease and with more nodal metastases.Conclusion: Calcitonin levels typically normalize within 1 week; and within a fortnight in those with node-positive MTC and preoperative calcitonin levels of 500⋅1-1000 pg/ml. With node-positive MTC and preoperative calcitonin levels exceeding 1000 pg/ml, and with more than ten nodal metastases, calcitonin normalization takes longer.

Medullary thyroid carcinoma: recent advances in identification, treatment, and prognosis

“…Calcitonin normalizes in a consistent pattern in node-negative patients with preoperative calcitonin levels <1000 pg/mL (3.5–6.6 days). 17 However, patients with node-positive disease with a preoperative serum calcitonin level >1000 pg/mL took on average 57.7 days to normalize compared to 6.6 days in those without nodal metastases. Length of time to calcitonin normalization was proportional to nodal burden of disease.…”

“…Those with more than 10 positive nodes demonstrated a mean time to calcitonin normalization of 57.1 days compared to 5.2 days in patients with 1–5 positive nodes and 7 days in patients with 6–10 positive nodes. 17 Thus, patients with calcitonin >1000 pg/mL and those with >10 positive lymph nodes have prolonged time to calcitonin normalization which must be considered when planning timing of first post-operative calcitonin level.…”

Unilateral Surgery for Medullary Thyroid Carcinoma: Seeking for Clinical Practice Guidelines

“…It should be noted that postoperative normalization of tumor marker Ctn takes time depending on the stage. Machens et al showed that this occurred at least one week postoperatively in MTC with LNM and preoperative Ctn level below 500 pg/ml, at least 14 days postoperatively in MTC with LNM and preoperative Ctn between 500.1-1000 pg/ml, and at a later time point in MTC with > 10 LNM and MTC with LNM and preoperative Ctn > 1000 pg/ml ( 6 ).…”

Prediction of biochemical cure in patients with medullary thyroid cancer

“…Current evidence suggests that the greater the number of node metastases from MTC, the higher the risk of distant metastases, and the lower the chance of biochemical cure and survival. The larger the number of node metastases removed, the longer the time to calcitonin normalization. Usually biochemical cure cannot be achieved when more than ten nodes are involved.…”